Currently wait_event_interruptible_timeout is called in cec_thread_func()
when adap->transmitting is set. But if the adapter is unconfigured
while transmitting, then adap->transmitting is set to NULL. But the
hardware is still actually transmitting the message, and that's
indicated by adap->transmit_in_progress and we should wait until that
is finished or times out before transmitting new messages.
As the original commit says: adap->transmitting is the userspace view,
adap->transmit_in_progress reflects the hardware state.
However, if adap->transmitting is NULL and adap->transmit_in_progress
is true, then wait_event_interruptible is called (no timeout), which
can get stuck indefinitely if the CEC driver is flaky and never marks
the transmit-in-progress as 'done'.
So test against transmit_in_progress when deciding whether to use
the timeout variant or not, instead of testing against adap->transmitting.
Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
Fixes: 32804fcb612b ("media: cec: keep track of outstanding transmits")
Cc: <stable@xxxxxxxxxxxxxxx> # for v4.19 and up
---
drivers/media/cec/cec-adap.c | 20 ++++++++++++--------
1 file changed, 12 insertions(+), 8 deletions(-)
diff --git a/drivers/media/cec/cec-adap.c b/drivers/media/cec/cec-adap.c
index d96add70b293..cf251f753b10 100644
--- a/drivers/media/cec/cec-adap.c
+++ b/drivers/media/cec/cec-adap.c
@@ -465,7 +465,7 @@ int cec_thread_func(void *_adap)
bool timeout = false;
u8 attempts;
- if (adap->transmitting) {
+ if (adap->transmit_in_progress) {
int err;
/*
@@ -500,7 +500,7 @@ int cec_thread_func(void *_adap)
goto unlock;
}
- if (adap->transmitting && timeout) {
+ if (adap->transmit_in_progress && timeout) {
/*
* If we timeout, then log that. Normally this does
* not happen and it is an indication of a faulty CEC
@@ -509,14 +509,18 @@ int cec_thread_func(void *_adap)
* so much traffic on the bus that the adapter was
* unable to transmit for CEC_XFER_TIMEOUT_MS (2.1s).
*/
- pr_warn("cec-%s: message %*ph timed out\n", adap->name,
- adap->transmitting->msg.len,
- adap->transmitting->msg.msg);
+ if (adap->transmitting) {
+ pr_warn("cec-%s: message %*ph timed out\n", adap->name,
+ adap->transmitting->msg.len,
+ adap->transmitting->msg.msg);
+ /* Just give up on this. */
+ cec_data_cancel(adap->transmitting,
+ CEC_TX_STATUS_TIMEOUT);
+ } else {
+ pr_warn("cec-%s: transmit timed out\n", adap->name);
+ }
adap->transmit_in_progress = false;
adap->tx_timeouts++;
- /* Just give up on this. */
- cec_data_cancel(adap->transmitting,
- CEC_TX_STATUS_TIMEOUT);
goto unlock;
}
--
2.23.0
